x1 is the conceptualized/ideal/abstract shape of a biconvex lens formed by/manifested from the intersection x2 (parameters) of two-dimensional circular disks immersed (embedded) in geometry/defined by metric x3; x1 is the convex-only region bounded by intersecting circular arcs given by x2
x1 is the conceptualized/ideal/abstract shape of a crescent/concave 'horned' (then convex rounded) form/geometric partially-concave lune formed by/manifested from the intersection x2 (parameters) of two-dimensional circular disks immersed (embedded) in geometry/defined by metric x3
x1 is the conceptualized/ideal/abstract shape of a crescent/concave 'horned' (then convex rounded) form/geometric partially-concave lune formed by/manifested from the intersection x2 (parameters) of two-dimensional circular disks immersed (embedded) in geometry/defined by metric x3
x1 is the idealized shape of an arbelos (bounded area; two-dimensional shape) wherein the largest circle has radius x2 and one smaller circle has radius x3, embedded in geometry/defined by metric x4.